Figure 5. Simplified phylogeny of Saurischia showing the main heterochronic trends of the skull.

Peramorphosis is colored in green and paedomorphosis in yellow. Grey trends indicate uncertain shape trends. Shape of the hypothetical ancestors based on the continuous character mapping of the Procrustes-fitted shapes of the adult terminal taxa from the original data set. Blue skulls represent ancestral skull shapes for which ontogeny could not be analysed. The heterochronic trends found in the regression analyses are visualized by the color of the branches. Possible heterochronic trends related to the skull evolution of allosauroids and basal coelurosaurs (see ‘Discussion’) are shown as dashed branches.